Very strange, the official vue.js guide linked in another comment gives me the same "corrupted content" error too. Unfortunately this makes me immediately suspicious of vue.js itself...

-e- FF 62.0b15 here, and both sites work in Chrome...

Same. Giving error "Corrupted content error" on Firefox 61.0.1 on Ubuntu 18.04 Bionic

Working fine for me in both Firefox and Chrome.